Mechanism for removal of air from paper-making machine feed stock



A. J. CIRRITO May 15, 1962 MECHANISM FOR REMOVAL. OF AIR FROMPAPER-MAKING MACHINE FEED STOCK Filed Jan. 25, 1958 2 SheetsSheet 1INVENTOR ANT/101V) 4/. C/Rfi/TO BY 4/ TLWQW ATTORNEY y 1962 A. J.CIRRITO 3,034,577

MECHANISM FOR REMOVAL OF AIR FROM PAPERMAKING MACHINE FEED STOCK FiledJan. 23, 1958 2 Sheets$heeo 2 f V V jzzz zzjifi I 9] M44; [1 2722% I Etlnited States atent tire 3,034,577 MECHANISM FOR REMOVAL OF AIR FRQMPAPER-MAKIYG MACHINE FEED STGCK Anthony J. Cirrito, Grafton, Mass,assignor to Rice Barton Corporation, Worcester, Mass., a corporation ofMassachusetts Filed Jan. 23, 1958, Ser. No. 710,762 8 Claims. (Cl.162-337) This invention relates to paper-making machines, and moreparticularly to apparatus for removal of air at stock inlets thereof.

One object is to make possible pressureor velocitytype flow channelstock inlets which run full of stock and free of air pockets.

Another object is to produce such results even at low slice flowvelocities, of the order of one hundred feet per minute, for example, ina pressure-type inlet.

Another object is to provide for delivery of a uniform and air-freesheet of stock at the slice, and to eliminate stagnant areas at whichair bubbles might collect adjacent slice attachments or hinges and theapproaches thereto.

In particular, it is an object of the invention to bleed olf from thetop of the inlet an air-rich layer of feed stock, thereafter separatingout the air and recycling the white water.

It is a further object to minimize cross-currents at the slot throughwhich the air-rich layer is led ofi and in the receiver into which saidslot enters by providing a multiplicity of conduits from said receiverto a vacuum or other relatively reduced pressure source.

Other objects, features and advantages will appear from the followingdescription of a preferred embodiment, taken together with the attacheddrawings of said preferred embodiment, in which:

FIG. 1 is a side elevation, partially in section, showing the newapparatus mounted on and in combination with a stock inlet of thevelocity type with slice attachment thereto;

FIG. 2, is an end elevation partially broken away;

FIG. 3 shows a portion of the view shown in FIG. 2, on an enlargedscale; and

FIG. 4 is a schematic view similar to FIG. 3 but on a reduced scale ofan alternative construction in accordance with the invention.

Referring now in greater detail to the drawings, there is shown in FIG.1 a typical Fourdrinier wire it) trained about conventional rolls 12 and14. A pressureor velocity-type inlet 15 defined by casing 16 is arrangedto discharge stock onto the wire 10 over an apron 25 having a lip 27,and has mounted therein perforated rolls 18, 2% and 22, for purposeswell known to the art. The upper wall of the inlet includes a member 3tand slice 28 forming no part of the present invention. Secured in theupper wall of the inlet 16 and extending therethrough is a generallycylindrical primary receiver 24 extending transversely across the entirewidth of the stock inlet 16, and provided across the bottom thereof witha slot 25 through which the top of the inlet 16 is in communication withthe interior of the receiver 24. The primary receiver 24 and slot 25 aremounted adjacent the slice attachment 8% the slot 25 being toward saidattachment 8% from the perforated roll 18, and being separated from theformer only by a smooth surface not adapted to permit any fluidstagnation forward of the slot 25. Extending tangentially rearwardlyfrom the top of the primary receiver 24 are a multiplicity of smallpipes 82, which may be, for example, one-inch pipes spaced 9 inchesapart, where the primary receiver 24 has an inside diameter ofapproximately 3 inches. In order to minimize cross-flow, the ratio of'distance between the centerlines of the small in the inlet 16).

pipes extending from the primary receiver should preferably not be morethan three times the inside diameter of said primary receiver. Includedin each line 82 may be a valve 84- as an aid to controlling the pressuredrop. All the lines 82 extend into the bottom of a second receiver 36,of diameter greater than the first receiver, for example 8 inches,mounted thereabove on fixed mounting 32 and also transversely of thepaper-making machine. The second receiver 86 is preferably slantedupwardly toward a separator or collector 83 to encourage foam risingtoward that end and eliminate possibility of stagnation at the opposingend. The diameter and physical characteristics of the second receiverare preferably chosen so that in operation the pressure drop across eachof the pipes 82 is approximately six or more times the pressure dropacross the entire width of the second receiver. Another method ofinsuring equal flows in each of the small pipes is to taper the secondreceiver as shown in FIG. 4 such that its area at the large endapproximates the sum of the areas of the pipes 82. Mounted above thecollector 83 is a dome 99 from the top of which extends apressurecontrol line 92, through which pressure (either vacuum orsuperatmospheric) may be imposed on the system (the only requirementbeing that the pressure be less than that The collector 8-3 functionstogether with the dome 9%} to act as a separator of the air and stock,stock falling through the drop leg 94 and air being pulled oif, undervacuum conditions, through the pipe 92. The drop leg as terminates atthe entrance of a magnetic flow meter 96 through which the white waterenters the tank $8 from which it is recycled through pump 1%. Alsoentering the top of the dome Sit) is a shower line 192 for adding theliquid to rinse the system and minimize foam build-up.

It will be understood that, according to the invention, the air richstock is drawn cit by differential of pressure depending upon fluidpressure existing in the stock inlet. If the latter is verysubstantially above atmospheric pressure, the lower pressure in thecontrol line 92 may well be also above that of the atmosphere in orderto achieve the desired flow. The use of the word vacuum in thisconnection is, therefore, purely relative.

In operation, the upper layer of stock flowing through the inlet 15, inwhich is known to accumulate the major portion or" entrapped air orfoam, is drawn up through the slot 25 extending across the entire inletinto the first receiver 24, from which it is in turn withdrawn from amultiplicity of smaller pipes 82 extending from the top of the firstreceiver, and adapted to be independently throttled to control at aconstant figure the pressure differential across the entire firstreceiver, to minimize or eliminate cross-currents therein. The mixtureof stock and foam is drawn through the pipes into the bottom of thelarger second receiver 86, and passes upwardly and transverselytherealong into the collector 88, air and liquid being separated thereinand in the dome 94 the liquid then being recirculated and the air beingremoved through the line 92.

It will be apparent that this invention provides the art with apparatusadapted to remove the free air from steel; flowing through inlets topaper-making machines adjacent the slice attachment so as to preventaccumulation of foam thereat and periodic discharge of foam therefrom,to the detriment of the paper structure, this being accomplished at thesame time without inducing cross-currents and while maintaining aconstant pressure differential across the entire width of the slotthrough which the air, as a part of the air-rich upper layer of stock,is withdrawn.

The invention makes possible, for example, achievement with astreamlined pressure-type inlet of slice velocities as low as onehundred feet per minute, whereas heretofore it has been necessary tooperate a large reservoir type of head box with a vacuum dome in orderto achieve these very low velocities. I

In addition to the preferred embodiment described herein, otherarrangements and variations within the spirit of the invention and thescope or" the appended claims will occur to those skilled in the art.The slice attachment, for example, might be a hinged rather than a rigidattachment as in the embodiment above described.

I claim:

1. In combination with a paper-making machine having an enclosed stockinlet including a slice attachment, a first receiver secured in theupper wall of said stock inlet across the entire width thereof inadvance of and adja cent said slice attachment, said first receiverbeing provided across the width thereof with a slot through which saidfirst receiver communicates with the interior of said stock inlet, asecond receiver mounted above said first receiver, a multiplicity ofconduits of diameter smaller than the diameter of said receiversextending therebetween, and means for imposing within the secondreceiver a predetermined pressure and for receiving therefrom liquid andgases withdrawn thercthrough.

2. The combination of claim 1 in which said second receiver is slantedupwardly toward and terminates at one end in a collector, the opposingend being sealed off.

3. The combination of claim 1 in which each of said conduits extendsfrom the top of the first receiver into the bottom of said secondreceiver, and in which the pressure drop across the width of said secondreceiver is less than one-sixth the pressure drop across one of saidcon-.

duits in operation.

4. The combination of claim 1 in which said conduits are spaced apart adistance not greater than three times the inside diameter of the firstconduit.

5. The combination of claim 1 in which each of said conduits has mountedtherein a valve as an aid to controlling the pressure drop therein.

6. The combination of claim 1 in which said first receiver and said slotare adjacent said slice attachment.

7. The combination of claim 1 wherein the second receiver is taperedwith its cross section increasing toward the discharge end and thecross-sectional area at this extremity approximating the sum of theareas of the multiple conduits while its area at the other extremityequals that of one of the multiple conduits.

8. In a paper making machine having an enclosed stock inlet including aslice attachment, the combination of a slot in advance of and adjacentthe web forming region in the upper wall of said stock inlet across theentire Width thereof, disposed to receive a shallow, even depthmachine-wide layer of stock from the uppermost portion of the main stockstream flowing through said inlet, a machine-wide transition zonedefined adjacent said slot, and in receiving communication with saidmain stream through said slot, a series of evenly spaced pipes disposedalong said transition zone, each in communication therewith at a pointspaced from said slot and generally in flow alignment with said slot,said transition zone being adapted to direct said machine-wide layer or"stock into said pipes and a receiver means communicating with the o,posite end of each pipe, adapted to impose a pressure drop condition oneach pipe relative to said stock inlet suitable to maintain balancedflow in said pipes whereby an even depth shallow layer of stock can beremoved from said main stream without disturbance of the stock flowconditions at the Web forming region.

References Cited in the file of this patent UNITED STATES PATENTS1,998,381 Mellentine Apr. 16, 1935 2,202,890 Berry June 4, 19402,344,282 Barry et al. Mar. 14, 1944 2,384,912 Helin Sept. 18, 19452,614,656 Clark et al. Oct. 21, 1952 2,677,316 Heys May 4, 19542,756,649 Lee July 31, 1956 FOREIGN PATENTS 1,093,016 France Nov. 17,1954 OTHER REFERENCES Van Der Meer, TAPPI, Nov. 1954, vol. 37, N0. 11,page 511.

